Re: [PATCH v2 03/12] arm_mpam: Set mpam_feat_msmon_mbwu_31counter when there are bandwidth counters

[James Morse]

Hi Ben,

On 17/09/2026 15:56, Ben Horgan wrote:
> When MPAMF_MSMON_IDR.MSMON_MBWU is 1, MSMON_MBWU is present and has a VALUE
> field of 31 bits. If additionally, MPAMF_MBWUMON_IDR.HAS_LONG is 1, then
> MSMON_MBWU_L is also present and has a VALUE field of 44 or 63 bits as
> indicated by MPAMF_MBWUMON_IDR.LWD. Hence, if there are memory bandwidth
> counters then there are always 31 bit counters irrespective of whether
> there also long counters.
> 
> Set the 31 bit bandwidth counter feature bit whenever there are bandwidth
> counters.

Yes, that bitmap is supposed to be what is present, not what the driver is choosing
to use.


> diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c
> index 32bde94dfbc3..e349db525882 100644
> --- a/drivers/resctrl/mpam_devices.c
> +++ b/drivers/resctrl/mpam_devices.c
> @@ -930,9 +930,9 @@ static void mpam_ris_hw_probe(struct mpam_msc_ris *ris)
>  						mpam_set_feature(mpam_feat_msmon_mbwu_63counter, props);
>  					else
>  						mpam_set_feature(mpam_feat_msmon_mbwu_44counter, props);
> -				} else {
> -					mpam_set_feature(mpam_feat_msmon_mbwu_31counter, props);
>  				}
> +
> +				mpam_set_feature(mpam_feat_msmon_mbwu_31counter, props);
>  			}
>  		}
>  	}


Reviewed-by: James Morse <james.morse@xxxxxxx>


Thanks,

James